58 lines
2.1 KiB
C#
58 lines
2.1 KiB
C#
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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using System.Windows;
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using System.Windows.Controls;
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using Microsoft.Xaml.Behaviors;
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namespace SWS.Commons.Helper.Behaviours
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{
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/// <summary>
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/// 让 WPF TreeView 支持 SelectedItem 双向绑定的行为类。
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/// 应用于 TreeView 后，可在 ViewModel 中直接使用绑定方式访问/设置选中项。
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/// </summary>
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public static class TreeViewSelectedItemBehavior
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{
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public static readonly DependencyProperty SelectedItemProperty =
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DependencyProperty.RegisterAttached(
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"SelectedItem",
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typeof(object),
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typeof(TreeViewSelectedItemBehavior),
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new FrameworkPropertyMetadata(
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null,
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FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
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OnSelectedItemChanged));
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// 获取附加属性值
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public static object GetSelectedItem(TreeView treeView) =>
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treeView.GetValue(SelectedItemProperty);
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// 设置附加属性值
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public static void SetSelectedItem(TreeView treeView, object value) =>
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treeView.SetValue(SelectedItemProperty, value);
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// 属性变化时的事件处理
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private static void OnSelectedItemChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
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{
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if (sender is TreeView treeView)
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{
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// 解耦旧事件处理器
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treeView.SelectedItemChanged -= OnTreeViewSelectedItemChanged;
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// 连接新事件处理器
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treeView.SelectedItemChanged += OnTreeViewSelectedItemChanged;
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}
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}
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// TreeView选择项变化时的处理
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private static void OnTreeViewSelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
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{
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var treeView = (TreeView)sender;
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// 更新附加属性值
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treeView.SetCurrentValue(SelectedItemProperty, e.NewValue);
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}
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}
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}
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